‘Depression gene' may have been ID'ed

If confirmed, it could be a good target for drug treatment.

By Don Finleydfinley@express-news.net

Updated 12:54 am, Saturday, October 29, 2011

Using a sophisticated new tool that could shine light on a number of mental disorders, scientists have identified a gene they say might play a role in major depression, in a study that included more than a thousand San Antonio volunteers.

The gene also appears to be a good target for drug treatment if the link to depression is confirmed, the scientists said.

“We were trying to come up with a way that could generally be used to link biological measurements to (psychiatric) disease risk,” said John Blangero, director of the AT&T Genomics Computing Center at the Texas Biomedical Research Institute. “And in our first application of this, in relation to major depressive disorder, we've actually come up with something quite exciting.”

Depression is one of the most common mental disorders, striking about 17 percent of adults during their lives. And while it long has been known to run in families, the search for genes has been frustrating — in large part because the defect in the brain that causes it isn't completely understood.

A method first developed at Texas Biomed for studying heart disease was adapted to see if it would work with mental disorders. It involves measuring 11,000 tiny sets of instructions for proteins produced by genes.

The tests were done on blood from 1,122 residents taking part in the San Antonio Family Heart Study. Among the volunteers, interviews and medical records found that more than 200 had suffered from depression at some point in their lives, and 86 were clinically depressed at the time of the interview.

David Glahn, an associate professor of psychiatry at Yale University who led the study, said the tests pointed to a substance produced by a gene called RNF123. While it hasn't previously been linked to depression, it has been shown to affect a part of the brain called the hippocampus, which is altered in people with major depression.

“We still have more work before we truly believe this is a home-run gene,” Glahn said. “We've got a really good candidate. Even that has been tough to do in depression.”

An existing drug has been shown to affect the gene, which Glahn said offers the possibility of a targeted drug therapy for depression if the results are confirmed.

“The current medications don't work as well as we might want,” he said.

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It might also lead to a way to predict who is at risk for depression, a disease that often first appears in the late teens or early adulthood. Blangero said the substance produced by the gene has an inverse relationship to depression — the more of it in the blood, the lower the risk of depression.

In that way, it's similar to levels of HDL cholesterol — the so-called good cholesterol — and heart disease. In fact, Blangero added, statistically speaking, low levels of the substance were a stronger predictor of depression than HDL cholesterol is of heart disease.